[openrqd] Add --help and other arguments for config overrides

**Is your feature request related to a problem? Please describe.**
openrqd does not provide a `--help` or other options for overriding config options.

**Describe the solution you'd like**
openrqd should have command line arguments for overriding config options.

The issue names openrqd but no files, tests, or entry point. Begin by locating openrqd's command-line entry point and configuration loading, then verify completion by checking that --help and config-override arguments are available.

Written by the indexing model from the issue text.